Frog and Tarantula Are Friends

Biology blog Tetrapodzoology reports on the adorable and repulsive tag team of Frog und Arachnid, livening up elephant dungheaps all over the world:

You might be surprised to learn that microhylids in Peru, India, Sri Lanka and perhaps elsewhere have developed close relationships with large spiders. One of the first published discussions of this phenomenon was produced by Crocraft & Hambler (1989). Noting a close association between individuals of the Dotted humming frog Chiasmocleis ventrimaculata and the burrowing theraphosid tarantula Xenesthis immanis in southeastern Peru (but read on), they suggested that the spider – well capable of killing and eating a frog of this size – used chemical cues to recognise the frogs. Young spiders have sometimes been observed to grab the frogs, examine them with their mouthparts, and then release them unharmed. Microhylids are probably unpalatable due to their skin toxins, and this might explain how this association arose in the first place [the image above shows a tarantula walking over a Dotted humming frog.

Apparently Yucky Frog and Savage Spider inhabit the same hidey holes, stand around the same patches of tree bark, and only tangle when the tarantula mistakes the frog for something delicious and reels it in for a good palping. Frog's skin chemicals save it further trauma, and they go about their business.

But the partnership goes further than that. While the presence of a massive tarantula noticeably lowers the presence of large frog-eating predators such as snakes, the frog eats ants that would carry off the tarantula's eggs. In the photo below, a clot of tarantulas are devouring a different sort of frog, while a wee microhylid frog stands by, pretending not to notice.

Stories like these force me to consider the perspective of the creatures involved. One cannot help imagining what it's like to feel comfortable, curled up in a hole with a prickly monster six times your size. Never knowing when she's going to grab you, stuff you in her mouth, and taste.

You can only hope that you stink in the proper way.

Tiny frogs and giant spiders: the best of friends [Tetrapod Zoology]